Zero axis crossing pulse modulator

Claim 1

A PULSE POSITION MODULATOR FOR CONVERTING AN APPLIED FREQENCY MODULATED SIGNAL TO A PULSE POSITION MODULATED SIGNAL WHICH COMPRISES, IN COMBINATION: A NEGATIVE RESISTANCE ACTIVE ELEMENT; MEANS INCLUDING A DIRECT CURRENT BIAS SOURCE AN ARESISTIVE LOAD IN CIRCUIT RELATION WITH SAID NEGATIVE REISITANCE ACTIVE ELEMENT FOR BIASING SAID ACTIVE ELEMENT NEAR INSTABILITY IN A BISTABLE CONFIGURATION SUCH THAT A FIRST STABLE STATE EXHIBITS A HIGH CURRENT-LOW VOLTAGE CHARACTERISTIC AND A SECOND STABLE STATE EXHIBITS A LOW CURRENT-HIGH VOLTAGE CHARACTERISTIC; MEANS INCLUDING A SOURCE OF FREQUENCY MODULATED SIGNALS FOR SUPERIMPOSING ON SAID DIRECT CURRENT BIAS APPLIED TO SAID ACTIVE ELEMENT AN ALTERNATING VOLTAGE OF SUFFICIENT MAGNITUDE WHEN PASSING THROUGH ZERO INTO THE POSITIVE HALF OF EACH CYCLE TO TRIGGER SAID ACTIVE ELEMENT FROM SAID FIRST STABLE STATE TO SAID SECOND STABLE STATE OF EACH WHEN PASSING THROUGH ZERO INTO THE NEGATIVE HALF OF EACH CYCLE TO TRIGGER SAID ACTIVE ELEMENT BACK TO SAID FIRST STABLE STATE; MEANS RESPONSIVE TO TRANSITIONS FROM SAID FIRST STABLE STATE TO SAID SECOND STABLE STATE AND FROM SAID SECOND STABLE STATE TO SAID FIRST STATE, INCLUDING A DIFFERENTIATOR, FOR PRODUCING A TRAIN OF SHARP SPIKES OF LARGE AMPLITUDE WHICH ACCURATELY MARKS SAID TRANSISTIONS; AND MEANS FOR UTILIZING SAID TRAIN OF SPIKES AS A PULSE POSITION MODULATED SIGNAL.